Completion Of Hemodialysis Research Articles

Postdialysis serum phosphate equilibrium in hemodialysis patients on a controlled diet and no binders.

Studies evaluating the change in serum phosphate post hemodialysis (HD) demonstrate an initial decline during dialysis but a rebound post dialysis. However, previous studies were done on usual diet and phosphate binders, with limited number of blood draws, confounding conclusions. We determined serum phosphate reduction, rebound, and equilibrium over 48 h in HD patients consuming a controlled, low phosphorus diet without binders. Serum phosphate (mg/dL) was analyzed before and after a HD treatment and frequently during the ensuing 48 h intradialytic period in the clinical research unit. Thirteen subjects were enrolled and had been off phosphate binders for 10 days and consumed a standardized low phosphate (900 mg/day) diet for 3 weeks prior to the assessments. Linear regression was used to determine relationships between the pre-HD serum phosphate, decline post-HD (post-HD drop); and a 48 h area under curve (AUC) using the trapezoidal method as a measure of overall phosphate levels from the end of dialysis to 48 h post dialysis. Repeated Measures ANOVA with Dunnett's posthoc test was used to determine rebound. Five of 13 subjects returned to >90% of their pre-HD serum phosphate within the first 24 h post-HD, and serum phosphate was 94 ± 0.11% (range 63%-113%) by 48 h after the completion of HD. The 48 h AUC of serum phosphate during the interdialytic period was correlated with both pre dialysis phosphorus (r=0.85; p=0.0002) and the pre-post drop in serum phosphate during dialysis (r=0.69; p=0.0085). In contrast, the net ultrafiltration was not related to the 48 h AUC of serum phosphorus (r=0.20; p=0.51). In hemodialysis patients on standard low phosphorus diet and no phosphate binders, the interdialytic serum phosphorus level, assessed as AUC, is determined by the pre dialysis phosphorus and net-change in serum phosphorus during the dialysis treatment, but not the ultrafiltration volume [Correction added on 25 January, after first online publication: In the last sentence of the Abstract, the word "potassium" has been replaced with "phosphorus" to improve accuracy.].

Feasibility of Intermittent Hemodialysis in Metformin Toxicity With Shock.

Metformin toxicity can lead to profound shock and has a high mortality rate. Supportive care and enhanced elimination are the mainstays of therapy. Intermittent hemodialysis (HD) produces a higher clearance of metformin than continuous veno-venous hemofiltration or hemodiafiltration (CVVH/HDF). Nevertheless, CVVH/HDF has been proposed as an alternative in critically ill patients with the suggestion that hypotension may limit the use of HD. This study sought to analyze the feasibility of performing hemodialysis in patients with persistent shock from metformin toxicity. We performed a 6-year (2012-2017) retrospective chart review of patients with metformin toxicity managed at a large academic institution with a toxicology service. We included patients with persistent shock on vasopressor support who were treated with HD. Baseline characteristics, complications from treatment, timing of dialysis, and differences between mean arterial pressures before, during, and at the end of dialysis were recorded and analyzed. Despite critical mean peak lactate (23.9 mMol/L [range 17.6-27.9]), pH (6.91 [range 6.78-7.01]), and metformin levels (range 25-58μg/mL], 6 of 7 patients recovered. All patients required prolonged HD (mean 19h). Upon completion of HD, hemodynamics had improved (45mm Hg [95% confidence interval 35-55mm Hg] vs. 80mm Hg [95% confidence interval 74-86mm Hg]) and vasopressor support decreased. Mortality in this patient cohort was 14.3% (1/7). Intermittent HD is feasible in metformin toxicity despite persistent shock and high-dose vasopressor support. Mean arterial pressures improved during the course of HD and high blood flow rates were tolerated.

Asymmetric dimethylarginine compartmental behavior during high-flux hemodialysis

Aim The accumulation of uremic toxins, such as asymmetric dimethylarginine (ADMA), has emerged as one of the major cardiovascular disease-related risk factors in patients with end-stage renal disease (ESRD). Based on the low molecular weight of ADMA, hemodialysis (HD) should theoretically effectively remove ADMA. In this study, we investigated the clearance behavior of ADMA during high-flux HD. Methods Eight HD patients without residual renal function were included. Blood samples were collected at 0, 30, 60, 120 and 240 min after dialysis started, as well as 1 h and 48 h after dialysis. ADMA level was detected by HPLC-MS/MS. Herein, the ADMA level in blood cells and the ADMA protein binding rate were measured. Accordingly, the dialyzer extraction ratio was also determined. Results The reduction ratio (RR) of ADMA (corrected for hemoconcentration) was significantly lower, at only 37.21 ± 6.44%, than that of urea and creatinine (p < .05). Interestingly, its clearance from plasma was precipitous early in dialysis and became slowly from 60 to 240 min. Additionally, a greater inlet erythrocyte than plasma concentration was found for ADMA. The dialyzer extraction ratio was comparable between ADMA and creatinine or urea (83 ± 5% for ADMA vs. 84 ± 3% and 88 ± 2% for creatinine and urea, respectively; both p>.05). Urea and creatinine had a slight rebound ratio of less than 10% at 1 h after the completion of HD. In contrast, considerable rebound of approximately 30% was detected in ADMA. Conclusion This study suggests that ADMA may present a multicompartmental distribution that cannot be representatively reflected by the urea kinetics model.

Changes in the inflammatory and oxidative stress markers during a single hemodialysis session in patients with chronic kidney disease

Background: Cardiovascular disease (CVD) is a common cause of morbidity and mortality in end-stage renal disease (ESRD) patients on hemodialysis (HD) among whom it is 5–20 times higher than in the general population. Some of the nontraditional risk factors such as oxidative stress and inflammation are related to the progress of CVD in HD patients. Several, but not all studies, reported that inflammatory and oxidative stress markers are increased during a single session of HD, mimicking changes that occur during acute immune activation. This study was taken up to evaluate the changes in the inflammatory and oxidative stress markers during a single HD session in patients with chronic kidney disease.Methods: Twenty-five ESRD patients on maintenance HD and 25 controls were included in the study. Blood samples were obtained from the patients before starting of hemodialysis (pre-HD) and after completion of hemodialysis (post-HD). The changes in serum Pentraxin-3, hs-CRP, malondialdehyde (MDA) and ferric reducing ability of plasma (FRAP) levels were measured in pre- and post-HD ESRD patients and compared with healthy control group.Results: This study found increased levels of Pentraxin-3, hs-CRP, MDA, and decreased level of FRAP in HD patients compared to controls.Conclusions: Hemodialysis procedure contributes to inflammation and oxidative stress.

Changes in Vascular Tone Occur Early During Hemodialysis Treatments Independently of Volume Reduction

Hypotension commonly occurs during hemodialysis (HD). Hypotension can result from an absolute reduction in plasma volume following excessive ultrafiltration or from a reduction in vascular tone. We hypothesized that changes in vascular tone could occur during dialysis. Aortic pulse wave velocity (aPWV) was measured in 197 HD patients, mean age 63.3 ± 16.6 years, 62% male, 49% diabetic, during a single HD session. aPWV did not change (9.6 ± 2.2 vs. 9.6 ± 2.2 m/s) with HD. Systolic blood pressure (SBP) declined from 151 ± 31 to 147 ± 32 after 20 min and to 140 ± 36 mm Hg on completion of HD (P < 0.05), with an ultrafiltration volume of 2.2 ± 0.9 L over a 3.9 ± 0.4 h HD session. Aortic SBP declined from 154 ± 32 to 146 ± 29 after 20 min and 143 ± 35 at the end of HD, P < 0.001. Aortic augmentation index (Aortic Aix) decreased from 65% (52-79%) to 36.7% (23.3-52.9%) by 20 min and to 34.3 (15.1-49.1%) on completion of HD (P < 0.05), and brachial augmentation index (brachial Aix) from 5.7% (-25.2 to 27.5%) to -1.9% (-2.2 to 30.1%) and -6.6% (-44 to 22.7%), respectively, P < 0.05. Diastolic reflection area (DRA) increased from 36.7 (27.9-46.3) to 40.4 (32.2-51) after 20 min and 47.1 (34.2-60.5) on completion of HD, P < 0.05. We report changes in arterial tone within 20 min of starting HD, when minimal ultrafiltration has occurred, suggesting that volume changes may not be the only predisposing cause of intradialytic hypotension. The combination of a fall in SBP and a rise in DRA would suggest a reduction in coronary blood flow in keeping with reports of "myocardial stunning" during HD.

Influence of hemodialysis on the plasma concentration of adenosine deaminase in patients with chronic kidney disease

Introduction: Over the past years there has been a significant increase in hospitalizations and treatments due to kidney complications that eventually resulted in the increased number of patients on dialysis. The adenosine deaminase (ADA) enzyme mediates the formation of some defense cells of the organism and is therefore a marker of inflammation. Objective: The objective of this study was to evaluate biomarkers of renal function and serum ADA of hemodialysis patients. Materials and methods: Blood samples were collected from 80 patients – 40 women and 40 men – between 19 and 60 years old, before and after the completion of hemodialysis. Results: There was a significant difference in levels of creatinine, urea and ADA in pre- and post-hemodialysis periods (p < 0.0001). There was a significant increase in post-dialysis ADA regardless of sex; however there was a significantly greater increase in men. Conclusion: The results showed a reduction in urea and creatinine parameters, evidencing the main purpose of hemodialysis. This study suggests that the determination of ADA activity could be used to monitor inflammation in hemodialysis patients, however wider and more specific studies are needed to show the effectiveness of serum ADA activity as an inflammatory marker in patients with chronic kidney disease.

Prognostic Significance of Cardiac Troponin-T Level in Chronic Kidney Disease Patients on Hemodialysis

Background: Cardiovascular complications are a major cause of mortality in chronic kidney patients (CKD) patients. More than 50% of patients of end-stage renal disease (ESRD) die due to these complication. Patients undergoing chronic hemodialysis (HD) presented with frequently elevated baseline values of cardiac troponin T (cTnT). Aim of the Study: The aim of this study was to estimate the level of cTnT in ESRD patients and to evaluate its diagnostic and prognostic value in HD patients. Materials and Methods: This was a case-control study carried over a period of 14 months. One hundred and one cases of CKD stage-V as per the KDIGO guidelines 2012 with eGFR ≤15 mL/min and 50 healthy control age-matched with a GFR ≥60 mL/min were included in the study. cTnT levels were measured at the start of the study, at 48 h and 6 months after completion of hemodialysis. Results: The mean age of the controls and cases were 45.74 ± 9.99 years and 47.77 ± 17.53 years, respectively. Of 101 cases, 40 cases had cTnT levels 0.10 ng/mL. Cardiac events were observed in 20 patients. Three patients died due to myocardial injury (cTnT levels >0.10 ng/mL) and 17 patients experienced cardiovascular events. These cardiovascular events were sudden cardiac deaths, stroke, atrial-ventricular block and congestive heart failure. Conclusion: All patients on chronic hemodialysis should be evaluated for annual measurement of serum cTnT, which could be used as a reference point. A small increase over time is common, but if any time levels more than double the baseline, which is uncommon, and if found indicate an acute coronary syndrome.

Urea rebound - some disadvantages of urea kinetic modeling

PURPOSE: The objectives of the present study are to determine the average urea rebound by examining the urea concentrations immediately after completion of hemodialysis (HD) and comparing these results to urea concentrations taken 30 min after the procedure (equilibrated values), to assess how the delivered dialysis dose changes when URR and Kt/V are calculated using each of these two values and to evaluate the significance of these differences and the reliability of the indicators in use. MATERIAL AND METHODS: The study covered 30 end-stage renal failure (ESRF) patients, 16 males and 14 females on chronic HD at a mean age of 43.90±10.63 years and average duration of dialysis treatment of 6.90±3.75 years. Average urea values were calculated for each patient using data from three consecutive monthly examinations taken immediately and 30 min after HD in order to determine the mean urea rebound percentage. RESULTS: Mean urea values in samples taken immediately and 30 min after HD showed statistically significant differences (p<0.05). Equilibrating urea concentration led to an average increase of 17.7% at the 30 min after HD. There was a statistically significant difference (p<0.05) between the calculated single pool Kt/V (1.23±0.11) and equilibrated Kt/V (1.17±0.18) as well as concerning mean URR values calculated by using non-equilibrated and equilibrated post dialysis urea (65.3±1.18% and 6.67±2.4%, respectively). CONCLUSION: Calculation of URR and single pool model of Kt/V for assessment of dialysis adequacy in ESRF patients on chronic HD results in overestimation of the delivered dialysis dose. These values differ statistically significantly from those when accounting for urea rebound. URR and Kt/Vsp indicators do not possess the necessary reliability as means to evaluate the delivered dialysis dose. Scripta Scientifica Medica 2013; 45(1): 71-74.

Hemodialysis-Induced P-Wave Signal-Averaged Electrocardiogram Alterations Are Indicative of Vulnerability to Atrial Arrhythmias

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, often occurring during hemodialysis (HD). Prolongation of the total filtered P-wave duration (PWD) and reduction of the root mean square voltages for the last 20 ms of the P wave (RMS20) on a P-wave signal-averaged electrocardiogram (P-SAECG) are predictors of AF. We investigated whether HD induces alterations of P-SAECG, and determined the influential factors. Thirty-three end-stage kidney disease patients (66.7 ± 12.6 years, 23 males) undergoing maintenance HD were enrolled in this study. Digital ambulatory P-SAECG monitoring and laboratory examination of serum proteins and ions were carried out before, during, and after the HD sessions. Data were analyzed by multiple regression analysis. PWD was significantly prolonged, and RMS20 significantly reduced, during HD. These values recovered after completion of HD. Multiple regression analysis showed that prolongation of PWD significantly correlated with HD duration and the rate of removal of body fluid. On the other hand, RMS20 significantly correlated with HD duration and blood urea nitrogen variation. HD resulted in prolongation of PWD and reduction of RMS20, indicating the vulnerability of HD patients to AF. These P-SAECG changes correlated with HD duration and the rate of removal of the body fluid. These findings underline the importance of the control of dialysis variables in the prevention of atrial arrhythmias following HD.

Effect Of A Dialysis Session On Plasma Branched Chain Aminio Acids In Hemodialysis Patients

AbstractProtein and amino acid (AA) metabolism is abnormal in End stage renal disease (ESRD). Hemodialysis (HD) procedure is a strong catabolic stimulus. Branched chain amino acids (BCAAs) can affect other AA levels by reducing AA efflux from muscle due to inhibition of muscle protein degradation. Essential amino acids and keto acid supplements including BCAA and branched-chain keto acid (BCKA) are proposed to decrease protein intake while maintaining protein status. This study was taken up to evaluate the effect of a dialysis session on plasma BCAA’s for which fifteen patients of ESRD on Maintenance HD, thrice a week were recruited into the study. Analysis was done on samples drawn at the beginning (pre-HD) and after the end of each dialysis session (post-HD). Plasma BCAA’s were estimated by Reverse phase High performance liquid chromatography using pre column derivatization with O-pthalaldehyde-Mercaptoethanol. A significant decrease in plasma concentration of Valine and Isoleucine were observed post-HD compared to the pre-HD levels (p&lt;0.05). After correcting the data by creatinine, the decrease in plasma concentrations of Valine and Isoleucine were still found to be statistically significant. The percentage losses after the completion of HD were –24.45, –23.19, and –6.22% respectively for valine, isoleucine, and leucine. The lower reduction in leucine could be due to its appearance from muscle catabolism during the dialysis session. In conclusion, hemodialysis itself may influence dialysate amino acid losses and may have an effect on muscle protein breakdown and this negative protein can be reversed with nutritional supplementation.

Relationship of Serum ADMA With pulmonary hypertension in patients on hemodialysis

AbstractBACKGROUNDAsymmetrical dimethylarginine (ADMA) is an endogenous nitric oxide (NO) inhibitor. Increased con‐centrations of serum ADMA may also contribute to endothelial dysfunction in patients with pulmonary vascular dis‐ease. Pulmonary hypertension in patients with end‐stage renal disease (ESRD) on hemodialysis is a newly described entity. The pathogenesis of pulmonary hypertension (PH) is considered to be ESRD‐related endothelial dysfunction. The aim of our study was to elucidate the possible relationship between serum ADMA and PH in patients undergo‐ing hemodialysis (HD).METHODSThe incidence of PH was prospectively estimated by Doppler echocardiography in 69 patients with ESRD undergoing long‐term HD (2 hrs of completion of HD). Serum ADMA levels were measured using the enzyme‐linked immunosorbent assay (ELISA) method. Pulmonary hypertension was defined as pulmonary artery systolic pressure (sPAP) &gt;35 mmHg as determined by Doppler echocardiography using the modified Bernouli equation. Then, the relationship between ADMA and pulmonary arterial pressure (PAP) was analyzed.RESULTSPulmonary hypertension was detected in 31.9% of patients receiving HD. Pulmonary artery systolic pressure was significantly higher in patients with PH compared with patients without PH (40.79 ± 12.32 versus 24.81 ± 4.54 mmHg; p &lt; .001), whereas the patients with PH had significantly higher cardiac output (6.41 ± 0.74 versus 5.08 ± 0.61 mL/min/m2, p &lt; .001). Serum ADMA levels were significantly elevated in patients with PH compared with those without PH and 25 matched control subjects (1.32 ± 0.15 µmol/L versus 0.99 ± 0.19 µmol/L versus 0.22 ± 0.05 µmol/L; p &lt; .001). Multiple regression analysis showed that sPAP was independently related to ADMA and arteriovenous fistula (AVF) flow (p &lt; .01).CONCLUSIONSIncreased ADMA levels and their positive association with PAP suggest that the NO pathway is involved in the development of pulmonary vascular disease.

P Wave Dispersion Increases during Hemodialysis Sessions

Background/Aims: Atrial fibrillation (AF) is common among hemodialysis (HD) patients and is associated with high mortality. P wave dispersion (PWD) is a noninvasive electrocardiographic marker of paroxysmal AF. Our aim was to evaluate the effect of HD session on PWD. Methods: Twenty-five patients (mean age 63 years, 10 males) with sinus rhythm and undergoing chronic HD treatment were included. Blood samples were drawn and 12-lead electrocardiograms were recorded immediately before HD session, at the 2nd hour during HD and at the end of the HD session. The difference between maximum and minimum P wave durations was calculated as PWD. Results: PWD significantly increased during HD sessions compared with predialysis values (41 ± 12 vs. 21 ± 10 ms, respectively, p < 0.001), then decreased to a value of 24 ± 7 ms at the completion of HD, which was not significantly different from the predialysis values. PWD during HD was significantly correlated with predialysis systolic and diastolic blood pressure (r = 0.42, p = 0.037, and r = 0.59, p = 0.002, respectively) and predialysis serum potassium level (r = 0.44, p = 0.031). Linear regression model revealed that predialysis diastolic blood pressure (p = 0.002), predialysis serum potassium level (p = 0.037) and the amount of ultrafiltration (p = 0.048) were the significant predictors of prolonged PWD during HD. Conclusion: PWD increases significantly during HD sessions. This may increase the risk of AF episodes during HD. High diastolic blood pressure and serum potassium level before HD and ultrafiltration amount may predict prolonged PWD during HD.

Massive gentamicin overdose in a 14-month-old

A healthy 14-month-old girl received gentamicin 500 mg (56 mg/kg) intravenously as empiric therapy given fever. The overdosage was quickly recognized and the child transferred to a pediatric referral center. Two hours after administration, serum creatinine was 0.3 mg/dl, though serum gentamicin level was 89 mg/L. Hemodialysis was initiated approximately 4 h after gentamicin was given and stopped 4 h later, with a serum gentamicin level of 3.4 mg/L. Gentamicin level 4 h after completion of hemodialysis was 2.3 mg/L. Three months later, the child's serum creatinine was 0.3 mg/dl, urinalysis showed no blood or protein, and audiometry showed normal hearing bilaterally at all frequencies. This child demonstrated the highest gentamicin level recorded in a patient with normal renal function. Her case demonstrates that prompt hemodialysis in this circumstance rapidly clears gentamicin without rebound. If left untreated, long-term adverse sequellae for hearing or renal function were possible; hemodialysis may have altered these outcomes.

Vasopressin administration facilitates fluid removal during hemodialysis

Inadequate secretion of vasopressin during fluid removal by hemodialysis may contribute to the cardiovascular instability that complicates this therapy and administration of exogenous hormone, by supporting arterial pressure, may facilitate volume removal. To test this, we measured plasma vasopressin in patients with end-stage renal disease (ESRD) during hemodialysis and found that despite significant fluid removal, plasma vasopressin concentration did not increase. We further found that ESRD did not alter the endogenous removal rate of plasma vasopressin and that plasma hormone is not dialyzed. Finally, in a randomized, double-blinded, placebo-controlled trial in 22 hypertensive patients, we examined the effect of a constant infusion of a non-pressor dose of vasopressin on the arterial pressure response during a hemodialysis in which the target fluid loss was increased by 0.5 kg over the baseline prescription. We found that arterial pressure was more stable in the patients receiving vasopressin and that while only one patient (9%) in the vasopressin group had a symptomatic hypotensive episode, 64% of the patients receiving placebo had such an episode (P=0.024). Moreover, increased fluid removal was achieved only in the vasopressin group (520+/-90 ml vs 64+/-130 ml, P=0.01). Thus, administration of non-pressor doses of vasopressin to hypertensive subjects improves cardiovascular stability during hemodialysis and allows increased removal of excess extracellular fluid. Inadequate vasopressin secretion during hemodialysis-induced fluid removal is a likely contributor to the intradialytic hypotension that limits fluid removal.

Assessment of dry weight by monitoring changes in blood volume during hemodialysis using Crit-Line

Routine assessment of dry weight in chronic hemodialysis patients relies primarily on clinical evaluation of patient fluid status. We evaluated whether measurement of postdialytic vascular refill could assist in the assessment of dry weight. Twenty-eight chronic, stable hemodialysis patients were studied during routine treatment sessions using constant dialysate temperature and dialysate sodium concentration, and relative changes in blood volume were monitored using Crit-Line III monitors throughout this study. The study was divided into three phases. Phase 1 studies evaluated the time-dependence of vascular compartment refill after completion of hemodialysis. Phase 2 studies evaluated the relationships in patient subgroups between intradialytic changes in blood volume and the presence of postdialytic vascular compartment refill during that last 10 minutes of hemodialysis after stopping ultrafiltration. Phase 3 studies evaluated the extent of dry weight changes following the application of a protocol for blood volume reduction, postdialytic vascular compartment refill, and correlation with clinical evidence of intradialytic hypovolemia and/or postdialytic fatigue. Phase 3 included anywhere from three to five treatments. Phase 1 studies demonstrated that despite interpatient variability in the magnitude of postdialytic vascular compartment refill, when significant refill was evident, it always continued for at least 30 minutes. However, the majority of refill took place within 10 minutes postdialysis. Phase 2 studies identified 3 groups of patients: those who exhibited intradialytic reductions in blood volume but not postdialytic vascular compartment refill (group 1), those who exhibited intradialytic reductions in blood volume and postdialytic vascular compartment refill (group 2), and those whose blood volume did not change substantially during hemodialysis treatment (group 3). In phase 3 studies, use of an ultrafiltration protocol for blood volume reduction and monitoring of postdialytic vascular compartment refill combined with clinical assessment of hypovolemia and postdialytic fatigue demonstrated that patients often had a clinical dry weight assessment which was too low or too high. In all 28 patients studied, dry weight was either increased or decreased following use of this protocol. Determination of the extent of both intradialytic decreases in blood volume and postdialytic vascular compartment refill, combined with clinical assessment of intradialytic hypovolemia and postdialytic fatigue, can help assess patient dry weight and optimize volume status while reducing dialysis associated morbidity. The number of hospital admissions due to fluid overload may be reduced.

Clearance of amino acids by hemodialysis in argininosuccinate synthetase deficiency

We determined the dialytic clearance of amino acids involved in ammoniagenesis and nitrogen excretion in a neonate with argininosuccinate synthetase deficiency who underwent acute hemodialysis. Plasma ammonia and plasma and dialysate amino acid concentrations were obtained at baseline, 30-minute intervals during hemodialysis, and 30 minutes after the completion of hemodialysis. Plasma ammonia concentrations declined by 56% during the 90-minute hemodialysis treatment, whereas arginine, citrulline, glutamine, and glycine concentrations decreased by 65%, 55%, 40%, and 34%, respectively. Mean dialytic clearances for arginine, citrulline, glutamine, and glycine were 24, 282, 263, and 189 mL/min per 1.73 m 2, respectively. The high dialytic clearance of citrulline suggests a novel mechanism of hemodialysis removal of nitrogen. Dialytic clearances of glutamine and glycine may prevent further ammoniagenesis in hyperammonemic patients. However, our data suggest that hemodialysis affects the precursors of alternative pathway removal of ammonia. Further study is needed to optimize the intradialytic and interdialytic dosing of substrates.

Peroxynitrite-induced oxidation of plasma lipids is enhanced in stable hemodialysis patients

The relationship between end-stage renal disease (ESRD), hemodialysis, and oxidative stress is controversial. To determine whether ESRD causes oxidative stress, we measured basal levels of plasma F2-isoprostanes as a marker of lipid peroxidation in vivo, and peroxynitrite-stimulated formation of F2-isoprostanes, as a marker of the oxidizibility of plasma lipids in vitro, before and after routine hemodialysis. Total plasma F2-isoprostanes were measured by gas chromatography-mass spectrometry (GC-MS) before and after the oxidation of plasma lipids with the peroxynitrite-generating compound, 3-morpholino-sydnonimine (SIN-1), in 23 patients with ESRD patients undergoing regular hemodialysis, and 14 controls. Plasma vitamin E concentrations were measured by high-performance liquid chromatography (HPLC). There was no difference in basal plasma concentrations of F2-isoprostanes in the ESRD group prior to hemodialysis, 246 +/- 20 pg/mL, compared to controls, 252 +/- 28 pg/mL, or immediately on completion of hemodialysis, 236 +/- 14 pg/mL. Incubation of control plasma with SIN-1 caused the formation of F2-isoprostanes with plasma concentrations increasing to 987 +/- 54 pg/mL at 6 hours. The formation of F2-isoprostanes stimulated by SIN-1 was markedly enhanced in the plasma obtained from patients undergoing hemodialysis at 1861 +/- 174 pg/mL, P < 0.001, and SIN-1-induced formation of F2-isoprostanes was further increased in plasma obtained immediately after hemodialysis at 2437 +/- 168 pg/mL, P < 0.001. Incubation of plasma with SIN-1 resulted in the net consumption of vitamin E. Although basal plasma F2-isoprostanes were similar in patients with ESRD compared with controls, the presence of oxidative stress in patients with ESRD was unmasked when the plasma was stressed by peroxynitrite generated from SIN-1, and this was enhanced further by hemodialysis.

Posterior ischemic optic neuropathy after hemodialysis

Purpose To report a case of visual loss from posterior ischemic optic neuropathy (PION) after hemodialysis. Design Observational case report. Methods Neuro-ophthalmic examination, neuro-imaging including computed tomography (CT) scan, magnetic resonance imaging (MRI) of the head and orbits, and magnetic resonance angiography (MRA) of the neck and cerebral vasculature, as well as electrophysiologic testing including electroretinogram (ERG) and visually evoked response (VER) were performed. Results Acute onset of painless bilateral no light perception vision with absent pupillary response to light and normal funduscopic examination occurred shortly after completion of hemodialysis. Computed tomography scan and MRA results were normal. Magnetic resonance imaging scan showed small vessel ischemic white matter changes. Electroretinogram results were normal and the VER was unrecordable. Conclusions Visual loss after hemodialysis is a rare complication and is associated with anemia and hypotensive events. The visual loss is usually a result of anterior ischemic optic neuropathy. We were unable to find another instance in the literature of visual loss after hemodialysis resulting from PION.

Clinical Effects of L-Threo-3,4-Dihydroxyphenylserine on Orthostatic Hypotension in Hemodialysis Patients

Orthostatic hypotension is one of the major factors interfering with everyday activities in hemodialysis patients, but there has been no effective agent for treating it. In order to clarify the clinical effects of L-threo-3,4-dihydroxyphenylserine (L-DOPS) on orthostatic hypotension of hemodialysis patients, we conducted a randomized, double-blind comparative trial. 149 regular hemodialysis patients with orthostatic hypotension were randomly allocated to three groups and L-DOPS at doses of 400 mg, 200 mg or placebo was orally administrated to each group 30 min before starting every hemodialysis for 4 weeks. Changes of blood pressure (BP) in orthostatic hypotension immediately after completion of hemodialysis and symptoms related to orthostatic hypotension were compared between the three groups. In the 400-mg group, systolic and diastolic BP after standing increased significantly and the drop of mean BP after standing was also reduced compared with pretreatment levels. No such changes were observed in the placebo group. Fatiguability, malaise/weakness, dizziness and light-headed feeling, the interdialytic symptoms commonly observed in hemodialysis patients who developed orthostatic hypotension, were improved to a significant extent in the L-DOPS group compared with the placebo group. In particular, the improvement was more remarkable for the L-DOPS 400-mg group than the placebo group in patients with diabetic nephropathy, lower systolic BP after standing, and the long duration type of orthostatic hypotension. The incidence of adverse events was comparable between the three groups, and all recovered after discontinuation of L-DOPS or concomitantly administered drugs, or without any treatment. These findings indicate that L-DOPS taken before hemodialysis prevents orthostatic hypotension in patients undergoing hemodialysis, and is also effective for the interdialytic symptoms related to orthostatic hypotension.

2424 Testosterone modulates neuron activity in the mesencephalic slice of japanese quail chick

Peroxynitrite-induced oxidation of plasma lipids is enhanced in stable hemodialysis patients.The relationship between end-stage renal disease (ESRD), hemodialysis, and oxidative stress is controversial. To determine whether ESRD causes oxidative stress, we measured basal levels of plasma F2-isoprostanes as a marker of lipid peroxidation in vivo, and peroxynitrite-stimulated formation of F2-isoprostanes, as a marker of the oxidizibility of plasma lipids in vitro, before and after routine hemodialysis.Total plasma F2-isoprostanes were measured by gas chromatography-mass spectrometry (GC-MS) before and after the oxidation of plasma lipids with the peroxynitrite-generating compound, 3-morpholino-sydnonimine (SIN-1), in 23 patients with ESRD patients undergoing regular hemodialysis, and 14 controls. Plasma vitamin E concentrations were measured by high-performance liquid chromatography (HPLC).There was no difference in basal plasma concentrations of F2-isoprostanes in the ESRD group prior to hemodialysis, 246 ± 20 pg/mL, compared to controls, 252 ± 28 pg/mL, or immediately on completion of hemodialysis, 236 ± 14 pg/mL. Incubation of control plasma with SIN-1 caused the formation of F2-isoprostanes with plasma concentrations increasing to 987 ± 54 pg/mL at 6 hours. The formation of F2-isoprostanes stimulated by SIN-1 was markedly enhanced in the plasma obtained from patients undergoing hemodialysis at 1861 ± 174 pg/mL, P < 0.001, and SIN-1–induced formation of F2-isoprostanes was further increased in plasma obtained immediately after hemodialysis at 2437 ± 168 pg/mL, P < 0.001. Incubation of plasma with SIN-1 resulted in the net consumption of vitamin E.Although basal plasma F2-isoprostanes were similar in patients with ESRD compared with controls, the presence of oxidative stress in patients with ESRD was unmasked when the plasma was stressed by peroxynitrite generated from SIN-1, and this was enhanced further by hemodialysis.